Self-injurious behavior (SIB) and other severe behavior disorders (SBD) represent a serious health problem for up to 17% of persons with mental retardation. Advances in disability law and behavior analysis have led to effective interventions for SBDs which are intensive and costly. Alternatively, prevention approaches could maximize developmental outcomes and minimize the costs of care. This project is designed to identify predictors of persistent SIB and other severe behaviors that can be used to target high-risk children in prevention studies. The experiment uses a single group, within-subjects design with repeated measures across nine time points involving approximately 40 families, and is optimal for an initial study about prediction of SBDs. Five factors previously demonstrated to be related to the persistence of SIB (parenting practices, child communication, caregiver depression, caregiver stress, and lack of social support) will be assessed quarterly over a two-year period using developmental testing, behavioral questionnaires, and direct observations of parent-child interactions. This investigation builds on a project partially funded by The Johns Hopkins General Clinical Research Center's Neurobehavioral Research Unit. The theoretical basis for this study is that SIB originates in early childhood and persists as a function of the interaction between a child's communication ability and parent responding to the child's communication and SIB. Specifically, children with poor communication skills, whose caregivers are less responsive to communication and more responsive to SIB, are at greater risk for persistent SIB. Parenting practices, in turn, are impacted by depression, stress, and social support, such that high levels of depression and stress, and low levels of social support likely decrease a parent's appropriate responsiveness to the child. Further, these relationships also can explain other severe behaviors which will also be quantified in this study. Because the most successful intervention for SBDs is based on this theoretical approach, we hypothesize that prevention should also. Understanding how to predict persistent SIB will then allow us to proceed with our intended research on how to prevent it. In addition to maximizing developmental outcomes for the child, early identification/prevention of SIB can avoid years of daily strife that can so negatively impact the entire family.